Method and system for data-driven, variable-rate, channel quality indicator for LTE non-real-time bursty traffic

ABSTRACT

A method and system, in a long term evolution architecture utilizing adaptive modulation and coding requiring periodic channel quality indication reports, the method having the steps of: waiting for an idle channel indication; and upon detection of the idle channel indication, decreasing the rate of periodic channel quality indication reports.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.11/741,590 filed on Apr. 27, 2007, the entire contents of which ishereby incorporated by reference for all purposes.

FIELD OF THE DISCLOSURE

The present disclosure relates to user equipment in a long termevolution (LTE) architecture, and in particular, to transmission ofchannel quality indications (CQI) in LTE.

BACKGROUND

In a long term evolution architecture, one technology being utilized isadaptive modulation and coding (AMC). AMC allows the modulation schemeand coding to be changed on a per-user basis depending on signal qualityand cell usage.

To facilitate AMC operations, in LTE, the user equipment (UE) isrequired to periodically report the channel quality indication (CQI),for example every two milliseconds. The CQI feedback for AMC incurssignificant overhead to both the uplink channel and the UE's batterypower due to the continuous CQI transmission.

Further, data traffic is often bursty and a UE could be idle for asignificant portion of time for which during which CQI feedback isongoing.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will be better understood with reference to thedrawings in which:

FIG. 1 is a flow diagram illustrating a UE centric method for decreasedCQI reporting rates during idle periods;

FIG. 2 is a flow diagram illustrating a UE centric method for decreasedCQI reporting based on a high layer indication;

FIG. 3 is a flow diagram illustrating a combination of the UE centricmethods of FIG. 1 and FIG. 2;

FIG. 4 is a flow diagram illustrating an ENB centric method fordecreased CQI reporting during idle periods;

FIG. 5 is a flow diagram illustrating the UE side of the method of FIG.4;

FIG. 6 is a block diagram of an exemplary mobile device for use with thepresent methods; and

FIG. 7 is a simplified enhanced Node B for use in association with thepresent methods.

DETAILED DESCRIPTION

The present disclosure relates to the reduction of CQI feedback impactto the UE's battery power and in one embodiment to the uplink channel.In particular, since most internet IP traffic has burstycharacteristics, during the time that there is no data for transmission,the AMC does not need to be used and CQI transmission is not necessary.

In a first embodiment, a UE centric solution is presented in which theCQI transmissions are reduced automatically if the UE determines thatthere is no traffic for a certain time. In this embodiment, the uplinkorthogonal frequency division multiplexing (OFDM) resources stillreserved for the uplink CQI transmission at the predefined periodicinterval, but the UE simply enters discontinuous transmit (DTX) forcertain CQI feedback slots, which can save the UE's battery power. Thiscan be implemented in several ways.

In one embodiment, a binary exponential algorithm can be applied. Inparticular, a threshold idle period (TIP) T can be set. If the UEdetermines that the measured idle period is greater than or equal to thethreshold T, the CQI reporting rate can be reduced by half. Similarly,if the measured idle period is >=2T, the CQI reporting can be reduced byone-quarter and so on.

In a second embodiment to the above, it is also possible for the UE toindicate to ENB concerning the reduced CQI reporting rate by someindication field, including a reservation field or an empty field, amongothers.

Further, full CQI information transmission may require 31 stages with 5bits. In some cases, only partial CQI information may be needed at thereduced transmission rate. The reason for this is that the overallchannel accuracy is already reduced by the reduced reporting rate.

Moreover, if a high layer, such as an application layer, can provide anyinformation about the ending of a particular data session, indicating anidle period may come, the UE can decide to reduce the CQI reporting rateimmediately rather than waiting for a threshold time to elapse.

In an alternative embodiment, an enhanced node B centric solution ispresented in which the enhanced node B can determine, based on thebuffer status of the eNB, to reduce CQI feedback from the UE. The eNBcan determine a new CQI reporting rate and format, and signal this tothe UE using in-band media access control (MAC) signaling. The UE canapply the new CQI reporting criteria to reduce the uplink feedbacktransmission as well as saving the UE's battery power. As will beappreciated by those skilled in the art, the uplink OFDM resource isalso released for the user's uplink use.

Recovery of CQI reporting for the above embodiments depends on whetherthe UE centric or the eNB centric solution is being utilized. In bothcases a recovery procedure preferably involves the eNB choosing the mostconservative modulation coding scheme (MCS) or the MCS based on thelatest CQI information for the transmission of data.

In the UE centric solution, the UE can recover by immediately startingfull rate CQI transmission upon receipt of the first data packets. Sincethe OFDM resource is already reserved for CQI transmission, the recoverydelay is negligible.

In the eNB centric solution, in-band MAC layer signaling could be usedto notify the UE about CQI reporting recovery. The rate can be dependenton the amount of data at the eNB that needs to be transmitted to the UE.

The present disclosure therefore provides a method, in a long termevolution architecture utilizing adaptive modulation and codingrequiring periodic channel quality indication reports, the methodcomprising the steps of: waiting for an idle channel indication; andupon detection of the idle channel indication, decreasing the rate ofperiodic channel quality indication reports.

The present disclosure further provides a user equipment for use in along term evolution architecture utilizing adaptive modulation andcoding requiring periodic channel quality indication reports, the userequipment characterized by: means for waiting for an idle channelindication; and means for decreasing the rate of periodic channelquality indication reports upon detection of the idle channelindication.

The present disclosure further provides an enhanced node B for use in along term evolution architecture utilizing adaptive modulation andcoding requiring periodic channel quality indication reports, theenhanced node B characterized by: means for waiting for an idle channelindication; and means for signaling a decrease in the rate of periodicchannel quality indication reports upon detection of the idle channelindication.

Unnecessary CQI reporting can be a drain on the battery resources of aUE and consume capacity at the air interface and network resources. Inparticular, for high speed downlink packet access (HSDPA), the highspeed dedicated physical control channel (HS-DPCCH) carries uplinkfeedback signaling related to downlink high speed downlink sharedchannel (HS-DSCH) transmission. The HS-DSCH related feedback signalingconsists of hybrid-automatic request acknowledgement (HARQ-ACK) andchannel quality indication (CQI). Each sub frame of length twomilliseconds consists of three slots, each length 2,560 chips. TheHARQ-ACK is carried on the first slot of the HS-DPCCH sub frame. The CQIis carried on the second and third slot of the HS-DPCCH sub frame. Eachslot can carry ten coded bits. The channel quality information is codedusing a (20,5). The CQI values 0 to 30 are converted from decimal tobinary to map then to the channel quality information bits (1 0 0 0 0)to (1 1 1 1 1) respectively. The HS-DPCCH physical channel mappingfunction maps the input bits directly to the physical channel so thatbits are transmitted over the air in ascending order. This presentssignificant cumulative transmission costs from a battery and networkperspective.

UE Centric Approach

Reference is now made to FIG. 1. FIG. 1 illustrates a flow diagram of amethod for a UE centric solution based on the idle period determination.

Once a UE has received traffic in step 110, the process proceeds to step112 in which a variable “X” is set to the current time.

The process then proceeds to step 114 in which a check is made todetermine whether the current time minus X is greater than or equal to athreshold. As will be appreciated by those skilled in the art, thethreshold is predetermined and the check of step 114 will determinewhether the threshold time has elapsed since the UE last receivedtraffic.

If, in step 114, the process determines that the threshold time has notelapsed, the process proceeds to step 120 in which the process checkswhether the UE has received traffic. If not, the process proceeds backto step 114 and continues to check whether the threshold time has beenexceeded or the UE has received traffic.

From step 120, if the UE receives traffic, then the process proceeds tostep 122 in which the CQI reporting period is reset to the full CQIresponse rate value to ensure that the AMC has sufficient information tomake a determination about the MCS.

If, in step 114, the threshold time has been exceeded, the processproceeds to step 130 in which it checks to see whether or not the delaybetween CQI reporting intervals has reached a maximum. As will beappreciated by those skilled in the art, it is undesirable to continuedecreasing the CQI reporting period indefinitely and thus a maximum CQIdelay between reporting intervals can be set.

If, in step 130, the process determines that the maximum CQI reportingdelay has not yet been reached, the process proceeds to step 132 inwhich the CQI reporting period is decreased. The process then proceedsback to step 112 in which the variable X is set to the current time.

Conversely, from step 130, if the maximum CQI reporting period has beenreached, the process proceeds directly to step 112 and skips step 132.In this way, the CQI reporting delay is not incremented beyond themaximum delay.

As will be appreciated by those skilled in the art, the process of FIG.1 is exemplary of a method to decrease the reporting rate of the CQIperiodically in order to save resources such as battery power on the UE.The method is not meant to be limiting.

The method of FIG. 1 allows the CQI reporting period to be incrementedperiodically. Specifically, each time the threshold T is exceeded, theCQI reporting rate is decreased to a maximum delay between CQI reportingintervals.

In one embodiment, the ratio of the reporting period can be inverselyproportional to the threshold T. Thus, when the idle period is greaterthan or equal to T, the CQI reporting rate is reduced by half. If themeasured idle period is greater than or equal to 2T, the reporting rateis reduced by 1/4, if the measured idle period is greater than or equalto 3T the reporting rate is reduced by 1/8, and so on.

By reducing the CQI reporting rate as above, the UE can save batteryresources. Specifically, the UE does not need to transmit at the presetreporting rate for standard AMC operation. Instead, the UE becomes DTXduring the time slots between the determined CQI reporting rate, andthus saves the UE's battery power. Thus, in full rate reporting the CQIreport would be sent in the first reporting interval, the secondreporting interval, the third reporting interval, and so on. If the CQIreporting rate is reduced by half, then the CQI report would be sent inthe first interval, the third interval, the fifth interval, and so on.Previous reports that would have been sent at the second, fourth, sixth,etc., intervals would not be sent.

The eNB determines the CQI transmission from the UE via blind detection.It is also possible for the UE to indicate to the UE about the reducedCQI reporting rate by some indication field. For example, a reservationfield or an empty field in the MAC header could be used for the CQIreporting to indicate that the reporting rate has been decreased. Aswill be appreciated by those skilled in the art, this could beimplemented, for example, in step 132 of the process of FIG. 1, wherestep 132 would, in addition to decreasing the CQI reporting rate,provide a indication to the eNB of the new reporting rate.

In addition, step 132 could also be used to change the amount of CQIinformation that the UE is required to report. In particular, iftransitioning to reduced rate CQI reporting, only partial CQIinformation may be needed. As will be appreciated, it is unnecessary inmost cases to continue sending full CQI at the reduced rate, since theoverall channel accuracy is already reduced by the reduced reportingrate. Thus, for example, instead of a 31 stage with 5 bits report, theCQI could be 8 stage with 3 bits. This also saves battery life andnetwork resources.

Reference is now made to FIG. 2.

FIG. 2 illustrates a flow chart for an alternative UE centric solution.In the embodiment of FIG. 2, the process begins at step 210 through thereception of an indication from a higher layer such as the applicationlayer that a particular data session has ended. This may occur, forexample, when a web page has been fully downloaded, and the browserapplication is aware of this.

The process then proceeds to step 212 in which a CQI reporting rate isdecreased immediately. As will be appreciated by those skilled in theart, since the data session has ended, the UE can assume that an idleperiod is to come and the process can thus immediately change the CQIreporting rate rather than waiting for idle thresholds as in FIG. 1.

The process then proceeds to step 214 in which it checks to see whetherdata has been received. If no, the process continues to loop in step 214until data is received. Once data is received in step 214, the processproceeds to step 216 in which the CQI reporting rate is reset to thefull CQI reporting rate and the process then ends at step 218.

Further, a combination of the embodiments of FIG. 1 and FIG. 2 couldalso be utilized. Referring to FIG. 3, a signal is received from ahigher layer that a data session has ended in step 310 and the processproceeds to step 312 in which the CQI reporting rate is immediatelydecreased.

From step 312, the process proceeds to step 316, which is equivalent tostep 112 of FIG. 1. In this way, the initial indication from the higherlayer that the data session has ended results in an immediate decreasein the CQI reporting rate. Subsequently, if no data is received, the CQIreporting rate can be further decreased through the process of FIG. 1,as illustrated in FIG. 3 where the process checks at step 318 whetherthe threshold has been exceeded, and if yes, and if the maximum delaybetween CQI reports has not been reached in step 330, then the CQIreporting rate can be decreased in step 332.

Step 316 can also be reached from step 314 in which traffic has beenreceived. Thus, in the embodiment of FIG. 3, the CQI reporting rate canbe decreased through one or both of an idle period for a threshold timeand/or a report from a higher layer such as the application layer.

From step 318, if the threshold has not been exceeded, the processproceeds to step 320 to check whether or not new traffic has beenreceived, and if yes, the process proceeds to step 322 in which the CQIreporting period is reset to the full reporting rate and the processproceeds back to step 316.

Recovery

As indicated in FIGS. 1, 2 and 3, steps 122, 216 and 322 provide for thestep of resetting the CQI to its full CQI transmission rate. As will beappreciated, the UE determines the idle period by itself and without anysignaling involvement. This can be through the lack of receipt of datafor a time period or from a message from a higher layer on the UE.

The resources for full rate CQI reporting on the network are unchangedby the methods of FIGS. 1, 2 and 3. Thus the UE can adjust the CQItransmission by itself and when new traffic activity occurs from theeNB, the UE automatically enters the full rate and full CQI transmissionto help the AMC. This reduces associated signaling overhead and therecovery delay is negligible since the uplink with the OFDM resource isstill reserved.

From the eNB perspective, since the eNB has not been receiving the CQIat the normal reporting rate, if new data arrives, the eNB chooses themost conservative modulation coding scheme (MCS) for the transmission tothe UE based on the latest received CQI information. After the UEreceives the first data packets, the UE immediately starts the full rateCQI transmission on the uplink as indicated in steps 122, 216 and 322 ofFIGS. 1, 2 and 3 respectively. This allows the MCS to be adjusted by theeNB.

ENB centric solution

Reference is now made to FIG. 4. For an eNB centric solution, the eNBchecks its buffer status for data for a particular UE. Specifically, theprocess starts at step 412 and proceeds to step 414 in which the processchecks whether the time that the buffer has been empty exceeds athreshold time. If no, the process continues to check step 414 until thebuffer empty time exceeds the threshold. As will be appreciated, thistime can be reset if new traffic arrives.

Once the buffer empty time exceeds the predetermined threshold, theprocess proceeds to step 416 in which the eNB determines a new CQIreporting rate. As with the UE centric solution, a reduced CQI reportingrate could also correspond with only partial CQI information beingrequired.

The process then proceeds to step 418 in which the new CQI reportingrate is signaled to a UE with in-band MAC signaling. This signalingcould also include the required CQI information to be sent.

The process then proceeds to step 420 in which the OFDM resource isreleased for the CQI periods that are no longer being used.Specifically, if the CQI was being reported every 2 milliseconds and hasnow been changed to every 4 milliseconds, the OFDM resource for everysecond CQI report can now be released.

The process then proceeds to step 422 in which it checks to see whetheror not traffic has been received by the buffer on the eNB for theparticular UE. If no, the process proceeds back to step 422 and waitsuntil traffic is received. Once traffic is received, the processproceeds to step 424.

Recovery

Once data is received, the eNB chooses a MCS for the transmission Instep 424. The eNB will typically choose the most conservative MCS fortransmission based on the latest CQI information.

The process then proceeds to step 426 in which the CQI recovery isreported to the UE. The eNB could use in-band MAC layer signaling tonotify the UE about the CQI reporting recovery.

Further, recovery does not necessarily require the CQI reporting to berestored to full rate and full information levels. For example, if theUE is currently at a 1/4 rate, 3 bit CQI transmission, if the eNBdetermines that there is only a small amount of data in the buffer, theeNB may notify the UE to use a half rate 5 bit CQI reporting.Conversely, if there is a huge amount of data coming to the buffer, theeNB may notify the UE to use its full rate 5 bit CQI for feedback.

The above in-band signaling is quite efficient for quick recovery.

To further save network resources, the CQI transmission pattern is, inone embodiment, predefined and will be indexed by 1, 2, 3, 4, . . . K,where K is a positive integer, and coded onto the layer 2 MAC optionalheader.

The process then proceeds to step 428 in which the traffic is passed tothe UE.

Once the buffer is empty, the process proceeds back to step 414 in whichit checks whether the buffer empty time exceeds the threshold.

As will be appreciated by those skilled in the art, the above embodimentof FIG. 4 can be modified to have incremental decreases in the CQIreporting rate. Specifically, if the buffer has been empty for an amountof time greater than a threshold, the eNB could signal to the UE toreduce the CQI reporting rate to a first value. If the buffer then isempty for an additional predetermined amount of time, the eNB couldsignal to the UE to use a second reporting rate. In this way, thereporting rate could be gradually decreased.

Reference is now made to FIG. 5. The process starts at step 510 andproceeds to step 512. From a UE perspective, the UE checks whether ornot it has received explicit signaling to change its CQI reporting rate.This explicit signaling is found in the in-band MAC layer signaling andcould, for example, be in the header of the MAC PDU.

From step 512, if a new CQI reporting rate has been received, theprocess proceeds to step 514 in which the UE adjusts the CQI reportingrate according to the value received in step 512. As will beappreciated, step 514 could also be used to indicate that only partialCQI information is necessary, and thus, to set the amount of informationthat is to be passed with each CQI report.

From step 514, the process proceeds back to step 512 in which the UEcontinues to monitor whether a new CQI reporting rate has been received.

As will be appreciated with reference to FIG. 5, the process can be usedfor both increasing and decreasing the CQI reporting rate. Thus, the UEcan increase the CQI reporting rate when data is pending and decreasethe CQI reporting rate when data transmission has finished, in responseto signaling from the eNB.

As will be appreciated with reference to FIGS. 4 and 5, the eNB centricsolution provides for the advantages of both battery life saving on theUE by reducing the CQI reporting rate and also releases the OFDMresource, thus saving network resources, which can be applied to othermobile devices. However, as will be appreciated, the signaling to notifythe UE of the resource can create delays and the eNB centric solutionalso requires explicit signaling between the UE and the eNB.

Reference is now made to FIG. 6. The above can be implemented on anymobile device. FIG. 6 illustrates an exemplary mobile device.

FIG. 6 is a block diagram illustrating user equipment apt to be usedwith preferred embodiments of the apparatus and method of the presentapplication. User equipment 600 is preferably a two-way wirelesscommunication device having at least voice and data communicationcapabilities. User equipment 600 preferably has the capability tocommunicate with other computer systems on the Internet.

User equipment 600 incorporates a communication subsystem 611, includingboth a receiver 612 and a transmitter 614, as well as associatedcomponents such as one or more, preferably embedded or internal, antennaelements 616 and 618, local oscillators (LOs) 613, and a processingmodule such as a digital signal processor (DSP) 620. As will be apparentto those skilled in the field of communications, the particular designof the communication subsystem 611 will be dependent upon thecommunication network in which the device is intended to operate.

An LTE user equipment may require a removable user identity module(RUIM) or a subscriber identity module (SIM) card in order to operate ona network. The SIM/RUIM interface 644 is normally similar to a card-slotinto which a SIM/RUIM card can be inserted and ejected like a disketteor PCMCIA card. The SIM/RUIM card can have approximately 64K of memoryand hold many key configuration 651, and other information 653 such asidentification, and subscriber related information.

When required network registration or activation procedures have beencompleted, user equipment 600 may send and receive communication signalsover a network 619. As illustrated in FIG. 6, network 619 can consist ofmultiple base stations communicating with the user equipment.

Signals received by antenna 616 through communication network 619 areinput to receiver 612, which may perform such common receiver functionsas signal amplification, frequency down conversion, filtering, channelselection and the like, and in the example system shown in FIG. 6,analog to digital (A/D) conversion. A/D conversion of a received signalallows more complex communication functions such as demodulation anddecoding to be performed in the DSP 620. In a similar manner, signals tobe transmitted are processed, including modulation and encoding forexample, by DSP 620 and input to transmitter 614 for digital to analogconversion, frequency up conversion, filtering, amplification andtransmission over the communication network 619 via antenna 618. DSP 620not only processes communication signals, but also provides for receiverand transmitter control. For example, the gains applied to communicationsignals in receiver 612 and transmitter 614 may be adaptively controlledthrough automatic gain control algorithms implemented in DSP 620.

User equipment 600 preferably includes a microprocessor 638 whichcontrols the overall operation of the device. Communication functions,including at least data and voice communications, are performed throughcommunication subsystem 611. Microprocessor 638 also interacts withfurther device subsystems such as the display 622, flash memory 624,random access memory (RAM) 626, auxiliary input/output (I/O) subsystems628, serial port 630, one or more keyboards or keypads 632, speaker 634,microphone 636, other communication subsystem 640 such as a short-rangecommunications subsystem and any other device subsystems generallydesignated as 642. Serial port 630 could include a USB port or otherport known to those in the art.

Some of the subsystems shown in FIG. 6 perform communication-relatedfunctions, whereas other subsystems may provide “resident” or on-devicefunctions. Notably, some subsystems, such as keyboard 632 and display622, for example, may be used for both communication-related functions,such as entering a text message for transmission over a communicationnetwork, and device-resident functions such as a calculator or tasklist.

Operating system software used by the microprocessor 638 is preferablystored in a persistent store such as flash memory 624, which may insteadbe a read-only memory (ROM) or similar storage element (not shown).Those skilled in the art will appreciate that the operating system,specific device applications, or parts thereof, may be temporarilyloaded into a volatile memory such as RAM 626. Received communicationsignals may also be stored in RAM 626.

As shown, flash memory 624 can be segregated into different areas forboth computer programs 658 and program data storage 650, 652, 654 and656. These different storage types indicate that each program canallocate a portion of flash memory 624 for their own data storagerequirements. Microprocessor 638, in addition to its operating systemfunctions, preferably enables execution of software applications on theuser equipment. A predetermined set of applications that control basicoperations, including at least data and voice communication applicationsfor example, will normally be installed on user equipment 600 duringmanufacturing. Other applications could be installed subsequently ordynamically.

A preferred software application may be a personal information manager(PIM) application having the ability to organize and manage data itemsrelating to the user of the user equipment such as, but not limited to,e-mail, calendar events, voice mails, appointments, and task items.Naturally, one or more memory stores would be available on the userequipment to facilitate storage of PIM data items. Such PIM applicationwould preferably have the ability to send and receive data items, viathe wireless network 619. In a preferred embodiment, the PIM data itemsare seamlessly integrated, synchronized and updated, via the wirelessnetwork 619, with the user equipment user's corresponding data itemsstored or associated with a host computer system. Further applicationsmay also be loaded onto the user equipment 600 through the network 619,an auxiliary I/O subsystem 628, serial port 630, short-rangecommunications subsystem 640 or any other suitable subsystem 642, andinstalled by a user in the RAM 626 or preferably a non-volatile store(not shown) for execution by the microprocessor 638. Such flexibility inapplication installation increases the functionality of the device andmay provide enhanced on-device functions, communication-relatedfunctions, or both. For example, secure communication applications mayenable electronic commerce functions and other such financialtransactions to be performed using the user equipment 600.

In a data communication mode, a received signal such as a text messageor web page download will be processed by the communication subsystem611 and input to the microprocessor 638, which preferably furtherprocesses the received signal for output to the display 622, oralternatively to an auxiliary I/O device 628.

A user of user equipment 600 may also compose data items such as emailmessages for example, using the keyboard 632, which is preferably acomplete alphanumeric keyboard or telephone-type keypad, in conjunctionwith the display 622 and possibly an auxiliary I/O device 628. Suchcomposed items may then be transmitted over a communication networkthrough the communication subsystem 611.

For voice communications, overall operation of user equipment 600 issimilar, except that received signals would preferably be output to aspeaker 634 and signals for transmission would be generated by amicrophone 636. Alternative voice or audio I/O subsystems, such as avoice message recording subsystem, may also be implemented on userequipment 600. Although voice or audio signal output is preferablyaccomplished primarily through the speaker 634, display 622 may also beused to provide an indication of the identity of a calling party, theduration of a voice call, or other voice call related information forexample.

Serial port 630 in FIG. 6 would normally be implemented in a personaldigital assistant (PDA)-type user equipment for which synchronizationwith a user's desktop computer (not shown) may be desirable, but is anoptional device component. Such a port 630 would enable a user to setpreferences through an external device or software application and wouldextend the capabilities of user equipment 600 by providing forinformation or software downloads to user equipment 600 other thanthrough a wireless communication network. The alternate download pathmay for example be used to load an encryption key onto the devicethrough a direct and thus reliable and trusted connection to therebyenable secure device communication. As will be appreciated by thoseskilled in the art, serial port 630 can further be used to connect themobile device to a computer to act as a modem.

Other communications subsystems 640, such as a short-rangecommunications subsystem, is a further optional component which mayprovide for communication between user equipment 600 and differentsystems or devices, which need not necessarily be similar devices. Forexample, the subsystem 640 may include an infrared device and associatedcircuits and components or a Bluetooth™ communication module to providefor communication with similarly enabled systems and devices.

Referring to FIG. 7, a simplified enhanced Node B 710 is provided.Enhanced Node B 710 includes a communications subsystem 712 forsignaling to user equipment and further for receiving data from anetwork.

Enhanced Node B further includes a buffer 714 to store data that is tobe passed to a UE.

Enhanced Node B further includes a processor 716 adapted to track datain buffer 714 and further to initiate signaling in accordance with theembodiment of FIG. 4.

The embodiments described herein are examples of structures, systems ormethods having elements corresponding to elements of the techniques ofthis application. This written description may enable those skilled inthe art to make and use embodiments having alternative elements thatlikewise correspond to the elements of the techniques of thisapplication. The intended scope of the techniques of this applicationthus includes other structures, systems or methods

The invention claimed is:
 1. A method performed at an enhanced node B,the method comprising: receiving channel quality indications from a userequipment at a first rate; determining a period of time for which abuffer on the enhanced Node B has been empty, the buffer being forstoring data for the user equipment; responsive to the period of time,signaling, utilizing a medium access control signaling, a decrease inthe rate of periodic channel quality indication reports to the userequipment; receiving channel quality indications from the user equipmentat the decreased rate; after the receiving, transmitting data to theuser equipment; and after the transmitting, receiving channel qualityindications from the user equipment at the first rate without signalingan increase in the rate of periodic channel quality indication reportsto the user equipment.
 2. The method of claim 1, further comprisingreleasing network resources required for channel quality indicationreporting.
 3. The method of claim 2, wherein the network resourcescomprise orthogonal frequency division multiplexing resources.
 4. Anenhanced node B comprising: a communications subsystem; a processor;wherein the communications subsystem and the processor cooperate to:receive channel quality indications from a user equipment at a firstrate; determine a period of time for which a buffer on the enhanced NodeB has been empty, the buffer being for storing data for the userequipment; responsive to the period of time, signal, utilizing a mediumaccess control signaling, a decrease in the rate of periodic channelquality indication reports to the user equipment; receive channelquality indications from the user equipment at the decreased rate; afterthe receiving, transmit data to the user equipment; and after thetransmitting, receive channel quality indications from the userequipment at the first rate without signaling an increase in the rate ofperiodic quality indication reports to the user equipment.
 5. Theenhanced node B of claim 4, wherein the communications subsystem and theprocessor further cooperate to release network resources required forchannel quality indication reporting.
 6. The enhanced node B of claim 5,wherein the network resources comprise orthogonal frequency divisionmultiplexing resources.
 7. A non-transitory computer readable mediumhaving stored thereon executable code for execution by a processor of anenhanced Node B, the executable code comprising instructions for:receiving channel quality indications from a user equipment at a firstrate; determining a period of time for which a buffer on the enhancedNode B has been empty, the buffer being for storing data for the rateequipment; responsive to the period of time, signaling, utilizing amedium access control signaling, a decrease in the rate of periodicchannel quality indication reports to the user equipment; receivingchannel quality indications from the user equipment at the decreasedrate; after the receiving, transmitting data to the user equipment; andafter the transmitting, receiving channel quality indications from theuser equipment at the first rate without signaling an increase in therate of periodic channel quality indication reports to the userequipment.
 8. The non-transitory computer readable medium of claim 7,the executable code further comprising instructions for releasingnetwork resources required for channel quality indication reporting. 9.The non-transitory computer readable medium of claim 8, wherein thenetwork resources comprise orthogonal frequency division multiplexingresources.